heavy hydrogen - WordReference.com Dictionary of English heavy hydrogen WordReference Random House Unabridged Dictionary of American English © 2017 heav′y hy′drogen, Chemistryeither of the heavy isotopes of hydrogen, esp. deuterium. Chemistrydeuterium. Collins Concise English Dictionary © HarperCollins Publishers:: heavy hydrogen n Forum discussions with the word(s) "heavy hydrogen" in the title: No titles with the word(s) "heavy hydrogen". What Is Deuterium? - Deuterium Facts Deuterium Facts Deuterium Facts What Is Deuterium? This is ionized deuterium in an IEC reactor. You can see the characteristic pink or reddish glow displayed by ionized deuterium. Benji9072 By Anne Marie Helmenstine, Ph.D. Updated November 01, 2016. What is deuterium ? Here's a look at what deuterium is, where you might find it, and some of the uses of deuterium. Deuterium Definition Hydrogen is unique in that it has three isotopes which are named. Deuterium is one of the isotopes of hydrogen. It has one proton and one neutron.

The most common isotope of hydrogen is protium , which has one proton and no neutrons. Because deuterium contains a neutron, it is more massive or heavier than protium, so it is sometimes called heavy hydrogen . There's a third hydrogen isotope, tritium, which may also be called heavy hydrogen because each atom contains one proton and two neutrons. Deuterium Facts The chemical symbol for deuterium is D. Sometimes the symbol 2H is used. Deuterium is a stable isotope of hydrogen. In other words, deuterium is not radioactive. The natural abundance of deuterium in the ocean is approximately 156.25 ppm, which is one atom in 6,400 of hydrogen. In other words, 99.98% of hydrogen in the ocean is protium and only 0.0156% is deuterium (or 0.0312% by mass). continue reading below our video 10 Facts About the Titanic That You Don't Know The natural abundance of deuterium is slightly different from one water source to another. Deuterium gas is one form of naturally occurring pure hydrogen.

It's chemical formula is written as either 2H2 or as D2. Pure deuterium gas is rare. It's more common to find deuterium bonded to a protium atom to form hydrogen deuteride, which is written as HD or 1H2H. The name for deuterium comes from the Greek word deuteros, which means "second". This is in reference two the two particles , a proton and a neutron, which make up the nucleus of a deuterium atom. A deuterium nucleus is termed a deuteron or deuton. Deuterium is used as a tracer, in nuclear fusion reactors and to slow down neutrons in heavy water moderated fission reactors. Deuterium was discovered in 1931 by Harold Urey. He used the new form of hydrogen to produce samples of heavy water. Urey won the Nobel Prize in 1934. Deuterium behaves differently from normal hydrogen in biochemical reactions. While it's not deadly to drink a small amount of heavy water , for example, ingesting a large quantity can be lethal. The presence of deuterium has been confirmed on other planets in the solar system and in the spectra of stars.

The outer planets have roughly the same deuterium concentration as each other. It is believed most of the deuterium present today was produced during the Big Bang nucleosynthesis event. Very little deuterium is seen in the Sun and other stars. Deuterium is consumed in stars at a faster rate than it is produced via the proton-proton reaction. Deuterium is made by separating naturally-occurring heavy water from a large volume of natural water. Deuterium could be produced in a nuclear reactor, but the method is not cost-effective. Isotope - definition of isotope by The Free Dictionary Isotope - definition of isotope by The Free Dictionary n. One of two or more atoms having the same atomic number but different mass numbers. [ iso- + Greek topos, place (so called because the isotopes of a chemical element occupy the same position in the periodic table of elements).] i′so·top′ic (-tŏp′ĭk) adj. i′so·top′i·cal·ly adv.

isotope (ˈaɪsəˌtəʊp) n (Chemistry) one of two or more atoms with the same atomic number that contain different numbers of neutrons [C20: from iso- + Greek topos place] isotopic adj (ˈaɪ səˌtoʊp) n. one of two or more forms of a chemical element having the same number of protons, or the same atomic number, but having different numbers of neutrons, or different atomic weights. [1913; iso - + Greek tópos place] i′so•top′ic (-ˈtɒp ɪk) adj. i`so•top′i•cal•ly, adv. i•sot•o•py (aɪˈsɒt ə pi, ˈaɪ səˌtoʊ pi) n. i·so·tope (ī′sə-tōp′) One of two or more atoms that have the same number of protons but a different number of neutrons. Carbon 12, the most common form of carbon, has six protons and six neutrons, whereas carbon 13 has six protons and seven neutrons.

ThesaurusAntonymsRelated WordsSynonymsLegend: Noun 1. isotope - one of two or more atoms with the same atomic number but with different numbers of neutrons atom - (physics and chemistry) the smallest component of an element having the chemical properties of the element radioisotope - a radioactive isotope of an element; produced either naturally or artificially deuterium , heavy hydrogen - an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen) Translations Chemical Molecule Library - Glossary Glossary Absorption In chemistry absorption can mean two things: Firstly it can imply that powerful forces exist holding two substances together, and that seperation of the two is not easily accomplished. Secondly it can mean absorption of heat, light etc.. . The absorption of ultraviolet, visible and infrared radiation is the basis of some forms of spectrometry which can be used to identify different chemical compounds. See also infrared radiation . Acid A substance that when dissolved in water dissociates and can donate a hydrogen ( proton ) to another molecule. Examples include sulphuric acid and nitric acid .

Under these conditions nitric acid dissociates according to the following equation: In water the protons attach themselves to the water molecules, giving the following equation: Actinides This is a group of elements within the periodic table and are also known as the transuranics. The name refers to those elements with increasing atomic no. from actinium, which all have similar chemical properties, like the lanthanides . The first few members of the group are the naturally occuring elements actinium, thorium, proactinium and uranium. Beyond this elements have been made artificially by radioactive bombardment. These artificial elements are unstable, some have very short lifeimes and undergo spontaneous radioactive decay. Adhesive Any compound that can stick two surfaces together is classified as an adhesive. Simple adhesives are of cellulose , starch and rubbers. Modern adhesives are based upon complex polymeric materials. The adhesive is spread in an unpolymerised form, and the adhesive properties increase as polymerisation occurs between the two surfaces. Adiabatic A chemical or mechanical process which takes place without heat entering or leaving the system. The term is only applicable to enclosed and isolated systems - so in essence is idealistic and purely theoretical and is important in the study of thermodynamics.

Adrenaline This was the first naturally produced hormone to be isolated it a pure state. It is known as epinephrine, but its chemical name is 1-[3,4-dihydroxyphenol]-2-methylaminoethanol. Its main action is to raise blood pressure, producing a faster pulse rate. Adsorption If any compound, solid, liquid or gas, is loosely held by weak attraction to the surface of a solid it is said to have undergone adsorption. This process is much weaker and less permanent than absorption . Air The air that we breathe is a mixture of gases. The composition of dry-air at sea level is shown below: Alchemy Several of the great Greek philosophers considered all matter to be composed of four basic "elements", fire, air, earth and water, and that all materials were had these components mixed in different proportions. If this theory was true, then it was believed that all substances could be converted (transmuted) into each other by varying the proportions of the mixture. This tansmutation theory was the basis of Alchemy from approx. 300 B.C.

to 1500 A.D., after which it slowly gave way to the more scientific concepts of chemistry from the 17th century onwards. The alchemists represented their "element" by a variety of symbols (see below), some of which were based on astrological signs They were mainly concerned with trying to turn base metals into gold and looking for the elixir of life although they also developed medicinal drugs, developed couterfeiting techniques and the debasement of precious metals. Alcohol An organic compound which has the general formula CnH2n+1OH, they consist of hydrocarbon chains terminated by hydroxyl groups, O-H. Smaller members are water soluble, flammable and are useful as organic solvents and fuels. As with hydrocarbons, each member differs from the previous by an additional -CH2- group. Alcohols with branced chains are also possible. Some of the simpler alcohols are listed below: Aldehyde An organic compound containing the -CHO group (see below). An example of these distinct aromatic compounds is formaldehyde . Alicyclic compounds An alicyclic compound contains rings of -CH2- units joined by single bonds.

Their general formula is CnH2n, the simplest member being cyclopropane. An example of these compounds is cyclohexane (see below): Alkali A water soluble hydroxide on one of the alkali metals. The term is virually synonymous with the term base . An example is Sodium Hydroxide, NaOH. Alkali metals Group I of the periodic table consists of the alkali metals. They are the most electropositive elements known, are monovalent, have low melting points and react violently with water. Alkaline earth metals Group II of the periodic table consists of the alkaline earth metals. They are bivalent and react with water to produce water soluble hydroxides. Alkaloid A naturally occuring organic compound containing nitrogen that acts as a base. Many alkaloids are physiologically active and can be used in small quantities as medicines, but if taken in larger doses they can be extremely poisonous. An example is caffeine . Alkanes This is the correct chemical term for compounds known as paraffins. They are considered the simplest organic compounds and are a family of chain hydrocarbons having the general formula C2H2n+2.

All of the bonds are single bonds (-C-H-, and -C-C-). The chains can be straight or branched. The smaller members (less than 4 carbons) are gases, while larger ones (five to seventeen carbons) are liquids. Beyond seventeen carbons the alkanes are waxy solids. Some simple alkanes are listed below: Alkenes These compounds are similar to alkanes , in that they can be straight or branched aliphatic hydrocarbons. The only difference is that the alkenes (also known as olefins) contain a carbon-carbon double bond, and have the general formula C2H2n. The simplest group member is ethene which is a gas. The double bond can be anywhere within the length of the carbon chain, resulting in a large number of possible isomers. The double bond means that these compounds are "unsaturated" and react readily with compounds capable of adding across the double bond. Some simple alkenes are listed below: Alkynes These compounds are also similar to alkanes . They have the general formula C2H2n-2 corresponding to carbon chains with a triple carbon-carbon bond included.

The simplest member of this family is ethyne (also known as acetylene). The triple bond makes these compounds very reactive. Some simple alkynes are listed below: Allotropy Certain chemical elements have the ability to exist in two or more different structural forms known as allotropes. These allotropes may possess different physical properties such as density and melting points. Allotropic elements include carbon , tin, phosphorus and sulphur. Each allotrope is stable within a certain range of temperature and pressure only, and under certain conditions an allotrope can be converted into another. Alloy An alloy consists of an intimate mixture of two elements, usually metals to give a metal compound or solid solution. Bronze is an alloy of copper and tin and brass on of copper and zinc. By varying the composition it is possible to alter the chemical and physical properties of the alloy such as conductivity, ductility and corrosion resistance. Alpha particles These are particles possessing a positive charge, and are emited from radioactive elements. The particles are actually helium nuclei, ie. helium atoms that had lost their outer electrons. The study of the alpha particle played a major part in the development of modern atomic theory. Rutherford bombarded other elements with alpha particles to produce nuclear disintegration.

Alum An alum is a double salt comprising a sulphate salt of a monovalent element, with the sulphate salt of a trivalent element. The most well known example is potash alum (aluminium potassium sulphate) KAl(SO4)2.12H2O which is used to clear murky water. Amalgam Liquid mercury has the ability to dissolve other metals to produce alloys and these alloys are called amalgams. Amalgam examples are gold/mercury, silver/mercury and copper/mercury all of which are used in dentistry. Amide An organic compound containing the -CONH2- group (see below). Also see peptide . Amine An amine is a distinctive smelling organic compound with one or more of the hydrogen atoms in ammonia replaced by organic groups. There are three classes of amines, dependant on the number of hydrogens replaced (see below): The organic groups can be aliphatic, alicyclic or aromatic, and some common amines are listed below: Amino group An organic compound containing the -NH2- group. Substances which contain this group are called amines . Examples include urea , and trimethylamine .

Amino acid A large class of substances with molecules including the amino and carboxyl groups.In the human body, amino acids are joined together to form long chains as part of the structures of proteins. Because they possess two functional groups, amino acids exhibit both acidic and basic characteristics. Each amino acid has an abbreviation when in a protein chain, so that the protein GlyAlaVal would indicate that a molecule of Glycine is joined to one of Alanine which is in turn joined to one of Valine. A list of the more common amino acids are given below: Anhydride These are compounds formed by the removal of water or Hydrogen and Oxygen together from another substance. In inorganic chemistry most anhydrides are formed by the loss of the water of crystallisation. eg. Copper(II) sulphate is a blue hydrated salt with the formula CuSO4.5H2O, but if heated, the water is driven off leaving the colourless anhydrous salt CuSO4. In organic chemistry an anhydride is usually the result of the loss of a water molecule from a dicarboxylic acid, eg.

from phthalic acid to give phthalic anhydride (see below): Anion A negatively charged ion or group of atoms. Antioxidant A substance which decrease the rate at which another substance is oxidised . An example includes BHA . Aromatic compound A substance containing one or more benzene rings. These compounds although unsaturated do not undergo normal reactions for unsaturated compounds as shown by their saturated open-chain analogues. This ability is related to the way in which their bonding electrons are spread evenly over the planar ring. Substances classified as being aromatic include those with one benzene ring such as: - or several rings such as: Certain other compounds can posses aromatic character - ie. they react in an aromatic manner even though they do not have the six-membered carbon ring. This group of compounds includes: Atactic A polymer is atactic if the groups attatched to the backbone are not arranged in any regular geometric pattern. Also see Isotactic . Atom The smallest part of an element that retains its properties. It is possible to "split" the atom up further into components; protons - which have a positive charge, electrons, which have a negative charge and neutrons which have no charge.

The simplest atom is hydrogen, which consists of a single proton nucleus and has a single electron forming an orbit or shell around the proton. The next simplest is helium, with two protons and two neutrons in the nucleus with two electrons orbiting within the shell - see selow for diagram: In all atoms the number of protons and electrons are the same but the number of neutrons can vary. Most of the mass of an atom is composed of the protons and neutrons, while the different isotopes of the same element vary in their number of protons, neutrons and electrons in the atomic structure. In some elements the arrangement of protons and neutrons in the nucleus is unstable, and the atom may disintegrate forming radioactivity. Azo dye An azo dye is one of an extensive range of synthetic organic dye made from aniline, by first converting it with sodium nitrite to a diazonium chloride salt which is then reacted with other aromatic amines, phenols and sulphonic acids.

The well known indicator methyl-orange is formed by making the diazo salt of sulphanilic acid, and reacting the product with dimethylaniline (see below): All azo compounds have the general formula Ar-N=N-Ar' with the characteristic -N=N- group in the middle. Base A substance that reacts with acid to produce a salt and water only. It does this by accepting a hydrogen ion from the acid . An example is ammonia which accepts a proton to become the ammonium ion - NH4+ Beta particles Radioactive elements can emit several types of radiation. Beta particles are very fast moving electrons. The particles have a velocity of between 30-99% speed of light, and it is this velocity which gives the beta particles greater penetrating power than alpha particles . Bond A chemical link between two atoms. In an ionic bond the attraction is between opposite charges on two neighbouring ions . In a covalent bond the two atoms share a pair of electrons. Carbanion This is an abbreviation of "carbon anion", and is applied to negatively charged ions that are believed to occur during organic reactions. The carbanion then reacts with positive species to produce new products.

To acquire a negative carbon ion it is necessary for the atom to retain two electrons forming a bond between itself and another group - see below: Carbonyl group An organic compound containing the >CO group (see below). When a hydrogen atom is attached to the carbon, the resulting compound is known as an aldehyde . When only carbon atoms are attached, the resulting compound is known as a ketone . See also carboxyl group and amide group . Carboxyl group An organic compound containing the -COOH group (see below), Where a carbonyl group is attached to a hydroxyl group. See also carboxylic acids . Carboxylic acid A substance containing the carboxyl group. The carboxylic hydrogen can be lost as a hydrogen ion , so these substances are also acidic . An example includes acetic acid . Carcinogen A substance capable of causing cancer in living organisms. It includes substances such as blue asbestos (crocidolite), which is a mineral, and benzene. Benzene has been used extensively for decades in chemistry and strict saftey guidlines must now be followed befrore it is used.

Any new pharmaceutical, cosmetic or food chemical has to be checked to ensure that they are not carcinogenic. Catalyst A substance that changes the rate at which a reaction equilibrium is attained, without itself being consumed. Catalysts can increase the rate of reaction (positive catalysts) or decrease them (negative catalysts or inhibitors). Cation A positively charged ion or group of atoms. Chain reaction A reaction where the product of one step is a reactant in a later step, which produces a reactant for a later step, and so on. Chiral Means "handedness" - A chiral or asymmetric molecule is one which can be distinguished from its mirror image. An example includes lactic acid . Cis-trans isomerism Compounds with double bonds, or alicyclic rings can exhibit isomerism, due to the attached groups lying above or below the plane of the oduble bond or ring. The "cis" compound is the one with the groups on the same side of the bond, and the "trans" has the groups on the opposite sides. The different isomers have different physical and chemical properties.

Examples are fumaric acid/maleic acid and 1,3-dimethylcyclohexane - see below: Combustion Combustion is the combination of a substance with oxygen in the presence of a flame accompanied by the production of heat and light. Combustion requires a supply of both fuel and oxygen (air) and can take place in the open atmosphere such as an open fire, or in a closed system, such as a car engine. Condensation reactions This is mainly an organic reaction where a simple molecule such as water or ammonia is eliminated when two molecules combine to produce another compound. A typical reaction is the esterification of an acid by an alcohol - in this case water is eliminated - see below: Condensation reactions reaction play a major part in the polymer industry for the synthesis or artificial polymers. Cross-links To increase the rigidity and density of synthetic polymers groups are introduced into the monomer molecules which enable bonds to form between polymer chains - this is known as cross-linking. The degree of cross-likning can have a marked effect on the physical properties of the final product.

An example are the silicones - they can vary from oils (low degree of cross-linking) to waxes (high degree of cross-linking). Crystal A discrete solid where the atoms,ions or molecules are arranged in an ordered 3-dimensional structure. The regular structures have the ability to "bend" or diffract beams of X-rays, and this aspect of crystallography is an extremely helpful tool in structure determination. Cyclic compounds A cyclic compound is one where the atoms are joined together so as to form a closed ring. Decomposition Where chemical compounds are broken up into simple molecules and even as far as their original elements. These processes are normally irreversible. An example of decomposition is when ammonium nitrate is heated. This produces nitrous oxide and water which are unable to recombine - see below: Detergents These are organic chemicals designed to clean surfaces or objects. They do this by reducing the surface tension and suspend dirt in suspension from the object to be cleaned.

Early detergents were long chain alcohol derivatives of sodium sulphate salts, such as sodium lauryl sulphate CH3(CH2)11O.SO2.ONa they were superseded by alkyl benzene sulphonates but these could not be broken down easily by bacteria at sewage works so these were eventually replaced by more eco-friendly detergents. Detergent molecules come in two parts - the sulphate or phosphate end (water soluble hydrophilic portion) and an organic hydrocarbon chain (water insoluble hydrophobic portion). Diazo compounds This is a series of organic compounds possessing the general formula Ar-N=N-Y, where Ar is an aromatic group and Y is any group linked to the nitrogen except via a carbon atom. They are different from the azo compounds which have the general formula Ar-N=N-Ar'. Diazo compounds are formed from amines by a two stage diazotisation reaction. Stage one is the conversion of an aromatic amine into a diazonium chloride salt using cold sodium nitrite and hydrochloric acid - see below: The second stage is the reaction of the diazonium chloride salt with an appropriate compound - such as another aromatic amine, eg.

the reaction with p-toluidine - see below: Distillation The separation and purification of a mixture of components by vapourisation followed by condensation, based on the different volatilities of each component. A typical experimental set up for distillation is shown below: Drug Any chemical compound used for medicianal purposes can be considered a drug. There are naturally occuring substances such as ethanol and caffeine as well as synthetic drugs such as aspirin and amphetamines . In general the term "drug" is used for compounds that can cause addiction with emphasis on narcotics. Dyes Dyes are chemical compounds that can attach themselves to fabrics or surfaces to give them colour. Most dyes are complex organic molecules and need to be resistant to many things such as the weather and the action of detergents. Indigo, otained from plants was being used by the Egyptians 5000 years ago, and natural dyes obtained from plants and animal sources are stil used today. In 1856, Perkin developed the first synthetic dye based upon aniline. Electromagnetic waves All matter absorbs and emmits radiation covering a broad band of frequencies and wavelengths .

This electromagnetic radiation has the velocity of the speed of light (2.998 x 108 ms-1) and arises from the vibrating electric charges in atoms and bonds. The range of wavelengths, also known as the electromagnetic spectrum is shown below: Electron An elementary negatively charged particle orbiting within an atom , the electrons are arranged in shells - and it is the outermost shell electrons which take part in bond formation. Electron pair Two electrons within one orbital with opposite spins responsible for a chemical bond . See also lone pair . Emulsion A dispersal, with a variety of industrial uses of one liquid as small particles in another liquid. An example would be milk . Enzyme A naturally occuring protein that fascilitates a specific biochemical reaction; a biological catayst . Ester A volatile fruity odoured product of the reaction between a carboxylic acid and an alcohol . Exothermic reaction The majority of chemical reactions are accompanied by the evolution of heat - these is known as exothermic reactions.

The reaction between an acid and a base is exothermic, it is possible to feel the temperature change when one is added to the other - see below: A rapid exothermic reation results in an explosion, as occurs when TNT explodes. Fatty acid A naturally occuring, usually in fats, monobasic carboxylic acid , with a long hydrocarbon tail chains. Ferromagnetism Many substances are found to be magnetic, in that they are attracted by magnetic and electric fields, but it is found that the metals iron, cobalt, nickel and a number of alloys posses a greater level of magnetism than other substances. This powerful magnetism is called ferromagnetism, and is due to a large magnetic moment in the atoms of the metals due to an unbalanced spin of the electrons in their inner orbits. Fluorescence The slow emission of longer wavelength light following the absorption of shorter wavelength radiation. Fluorescence is common with aromatic compounds with several rings joined together. Phosphorescence is similar but may persist long after the stimulating radiation is extinguished. Gamma rays One of the three types of rays produced by radioactive disintegration, but gamma rays are the only one comprised of electromagnetic radiation.

Gamma rays have a very short wavelength, and have the greatest penetrative power of all radioactive emissions. Glycols Glycols are compounds that have two hydroxyl groups present in each molecule. The simplest member is ethylene glycol - see below: Halogens This important group of elements occupies Group VII of the periodic table . Its first element, fluorine, is the most strongly electronegative element known. All halogens are electron defficient and readily share electrons with other elements to staisfy their valency needs, eg. they all form compounds with hydrogen, with the formula HX (where X=halogen) Heavy water A molecule of water contains two atoms of hydrogen and one of oxygen. Most water comprises of hydrogen/oxygen but a small percentage is composed of another hydrogen isotope, deuterium and oxygen. Deuterium differs from hydrogen by having one neutron in the nucleus of each atom. Deuterium water is given the formula D2O. There is approx. 1 part in 5000 D2O in normal water and it can be concentrated by electrolysis.

D2O had a higher boiling point (101.4 °C) and melts at 3.6 °C Heterocyclic molecule A molecule containing at least one ring of carbon atoms, and which also has at least one atom from a different element, (nitrogen, sulphur, oxygen etc..) within the ring. Examples are shown below: Hydrocarbon A molecule comprised solely of carbon and hydrogen. The simplest example is Methane . Hydrogen bond A bond formed by a hydrogen atom to an electronegative atom, and is denoted X---H-B. Hydrogen ion The ion which is left when the hydrogen atom loses its electron, forming a proton. In water the hydrogen ion binds to the water molecules, producing H3O+. Compound which exhibit hydrogen bonding include water and amines . Indicators A number of complex organic molecules can change their molecular structure and colour when faced with different pH conditions. The most well known indicator is litmus, which is a mixture of vegetable dyes. A list of common synthetic dyes is given below: Infrared radiation Electromagnetic radiation whose wavelength is longer than that of visible light, and is responsible for the transmission of radiant heat.

Ion An electrically charged atom or group of atoms. If an atom or molecule gains an electron - it becomes a negatively charged anion, or if it loses an electron it becomes a positively charged cation. Isomerism If a molecule possesses the same molecular formula, but the atoms are arranged in a different way, then they are called isomers. Isomers have different physical and chemical properties from each other. Optically active isomers differ only in the fact one is the mirror image of the other, as shown with lactic acid below: Many isomers occur as a result of different substituents occupying different positions on a benzene ring - see below: Isotactic Means geometrically regular. A polymer is isotactic if all of the groups attched to the back bone are arranged in the same geometrical pattern. See atactic . Isotopes All atoms of the same element posses the same no. of protons and electrons but not neccarily the same no. of neutrons. So all atoms of an element will react in the same way, but they can differ in their molecular masses. Atoms of the same element with different masses are known as isotopes. Hydrogen has three isotopes.

99.98% of all hydrogen has one proton and one electron, while 0.02% of hydrogen has one proton, one neutron and one electron. This isotope is called deuterium. There is also a trace of a third isotope, tritium, which has two neutrons in its nucleus. Ketone An organic compound containing the carbonyl group, >C=O, to which other carbon atoms are attached. Ketones are extremely useful as solvents and paint components. An example is Butanedione . Lanthanides This is a group of fifteen closely related elements and are known as the rare earth or "inner transition" elements. They are so alike that they are difficult to seperate from each other and usually all occur together in nature. Lipid A naturally occurring substance soluble in organic solvents but not in water. Molecule A molecule is two or more atoms joined together by chemical bonds. This may result in two atoms of the same molecule, such as chlorine, Cl2, or by combining elements as in ammonia, NH3. A molecule can be considered the smallest unit representitve of that compound which possesses all its properties. Lone pair A pair of electrons not involved in bond formation.

Monomer A monomer is a starting material or single unit from which a polymer is built. It refers to the repeat units that make up the polymer chains. Ethylene is the monomer for polyethylene and styrene for polystyrene. Neutron One of the three fundamental particles which form atoms, the neutron has the mass of a proton but no electrical charge. Neutrons are emitted when large atomic nuclei are bombarded with alpha particles. Noble gases This collection of elements make up Group 0 in the periodic table . They were known as inert gases for many years but that has changed with the reports of noble gas compounds. They are all gaseous elements found in the atmosphere, except for radon which is formed from the radioactive decay of uranium. The elememts are inert due to their stable electronic configuration. The gases are useful as inert atmospheres for reactions that must exclude oxygen, for balloons (helium) and for lighting displays. Oxidation This is a reaction with oxygen, as in combustion. An oxidized molecule is generally one that has lost electrons. Reduction also takes palce during oxidation - if one substance is oxidised then anothr must be reduced.

Parrafin An organic compound containing the group -CONH (see below), examples of which are polypeptides . Periodic table Early alchemists understood that certain elements could be grouped together due to the properties that they had. But it was not until the 18th century that Lavoisier tried to classify the known elements. It took another 100 years and a lot of trial and error for Mendeleev to propose a real foundation for the modern periodic table. He arranged the elements in a table according to relative atomic mass and left gaps where an element did not match. By doing this he could predict where a new element should come and what properties it should have. pH Acidity and alkalinity of aqueous solutions are axpressed in terms of pH. This is a measurement of the hydrogen ion concentration of the solution. Mathematically it is expressed as: The pH scale of 0-14 covers the range from strong acid to strong base. A neutral solution has the same number of hydrogen ions and hydroxyl ions and this corresponds to pH 7. Values higher than pH 7 are alkaline, whereas if they are lower than pH 7 they are acidic.

Phenol An organic substance in which a hydroxyl group is attached directly to a benzene ring. An example is vanillin . Photochemical reaction A chemical reaction can be enhanced when induced by light, just as some are speeded up by catalysts. Chlorine is one of a number of substances that undergo photochemical reactions. In sunlight, chlorine will react with carbon monoxide to produce the poisonous gas phosgene: A large number of organic reactions are carried out by irradiating with ultraviolet light. Photon All matter absorbs and emits electromagnetic radiation in discrete small quantities called photons. The energy of a photon (E) varies withthe frequency of the radiation according to: - where h is a constant known as Planck's constant. Polymer A polymer is a long chain molecule or a complex 3-dimensional lattice produced by the reaction of simple compounds with each other. There are two types of poymerisation. The first, where compounds open a double bond and link together via the radicals formed is called addition polymerisation. eg.

the poylmerisation of propylene to polypropylene: The other main type of polymerisation is condensation polymerisation, where as with condensation reactions , a simple molecule is eliminated during the formation of the polymer, eg. the reaction between adipic acid and hexamethylenediamine to produce nylon: Protein A molecule comprised of long chains of amino acid molecules. Proteins, which include enzymes , are polypeptides . Proton One of the three fundamental particles in atoms. Protons carry a large positive charge, is of similar mass as the neutron but is 1836 times as heavy as an electron. Radical A radical is a reaction intermediate where a bond is broken and the two parts of the molecule exist carrying a single unshared electron. The radicals are normally destroyed quickly by recombination or they break in another radical and a stable molecule. Reduction The addition of hydrogen and the removal of oxygen - the oppposite to oxidation , but is now generalised to the inclusion of electrons to a substance by any means. Salt The ionic product of a reaction between an acid and a base . Water is also formed Saturated compound An organic compound that does not comprise of carbon-carbon multiple bonds.

Examples include ethane and propane . Solvent A solvent is a substance capable of reataining its physical state whilst forming a homogenous mixture with one or more substances. Some common solvents are listed below: Surfactant A surface-active agent; one that accumulates at the interface between two liquids and modifies their surface properties. An example would include the sterate ion. Transmutation The conversion of one element into another by a process taking place in the nucleus. Ultraviolet light Electromagnetic radiation with a wavelength shorter than that of visible light. Unsaturated compound An organic compound that contains carbon-carbon multiple bonds. Examples include ethene and propene . Vitamins The name vitamins is obtained from "vital amines" as it was originally thought that these substances were all amines. This is now known not to be as vitamins have a range of structures. The body requires a small amout of vitamins, but any deficiency leads to metabolic and physical disorders.

Wavelength deuterium | chemical isotope | Britannica.com chemical isotope physical science Deuterium, (D, or 2H), also called heavy hydrogen, isotope of hydrogen with a nucleus consisting of one proton and one neutron , which is double the mass of the nucleus of ordinary hydrogen (one proton). Deuterium has an atomic weight of 2.014. It is a stable atomic species found in natural hydrogen compounds to the extent of about 0.0156 percent. Deuterium was discovered (1931) by the American chemist Harold C. Urey (for which he was awarded the Nobel Prize for Chemistry in 1934) and his associates Ferdinand G. Brickwedde and George M. Murphy. Urey predicted a difference between the vapour pressures of molecular hydrogen (H2) and of a corresponding molecule with one hydrogen atom replaced by deuterium (HD) and, thus, the possibility of separating these substances by distillation of liquid hydrogen. The deuterium was detected (by its atomic spectrum) in the residue of a distillation of liquid hydrogen. Deuterium was first prepared in pure form in 1933 by Gilbert N.

Lewis , using the electrolytic method of concentration discovered by Edward Wight Washburn. When water is electrolyzed —i.e., decomposed by an electric current (actually a water solution of an electrolyte , usually sodium hydroxide, is used)—the hydrogen gas produced contains a smaller fraction of deuterium than the remaining water, and, hence, deuterium is concentrated in the water. Very nearly pure deuterium oxide (D2O; heavy water) is secured when the amount of water has been reduced to about one hundred-thousandth of its original volume by continued electrolysis. hydrogen (H): Isotopes of hydrogen Deuterium enters into all chemical reactions characteristic of ordinary hydrogen, forming equivalent compounds . Deuterium, however, reacts more slowly than ordinary hydrogen, a criterion that distinguishes the two forms of hydrogen. Because of this property, among others, deuterium is extensively used as an isotopic tracer in investigations of chemical and biochemical reactions involving hydrogen. The nuclear fusion of deuterium atoms or of deuterium and the heavier hydrogen isotope, tritium , at high temperature is accompanied by release of an enormous amount of energy; such reactions have been used in thermonuclear weapons .

Since 1953, the stable solid substance lithium deuteride (LiD) has been used in place of both deuterium and tritium. The physical properties of the molecular form of the isotope deuterium (D2) and the molecules of hydrogen deuteride (HD) are compared with those of the molecules of ordinary hydrogen (H2) in the Table. Comparison of the physical properties of molecular forms of hydrogen ordinary hydrogen Chemistry of Hydrogen - Chemistry LibreTexts Chemistry of Hydrogen Contributors Hydrogen is a colorless, odorless and tasteless gas that is the most abundant element in the known universe. It is also the lightest (in terms of atomic mass) and the simplest, having only one proton and one electron (and no neutrons in its most common isotope). It is all around us. It is a component of water (H2O), fats, petroleum, table sugar (C6H12O6), ammonia (NH3), and hydrogen peroxide (H2O2)—things essential to life, as we know it.

Hydrogen Facts At Room Temperature: Colorless & Odorless Diatomic Gas History of Hydrogen Hydrogen comes from Greek meaning “water producer” (“hydro” =water and “gennao”=to make). First isolated and identified as an element by Cavendish in 1766, hydrogen was believed to be many different things. Cavendish himself thought that it was "inflammable air from metals", owing to its production by the action of acids on metals. Before that, Robert Boyle and Paracelsus both used reactions of iron and acids to produce hydrogen gas and Antoine Lavoisier gave hydrogen its name because it produced water when ignited in air. Others thought it was pure phlogiston because of its flammability. Hydrogen is among the ten most abundant elements on the planet, but very little is found in elemental form due to its low density and reactivity. Much of the terrestrial hydrogen is locked up in water molecules and organic compounds like hydrocarbons. Properties of Hydrogen Hydrogen is a nonmetal and is placed above group in the periodic table because it has ns1 electron configuration like the alkali metals.

However, it varies greatly from the alkali metals as it forms cations (H+) more reluctantly than the other alkali metals. Hydrogen‘s ionization energy is 1312 kJ/mol, while lithium (the alkali metal with the highest ionization energy) has an ionization energy of 520 kJ/mol. Because hydrogen is a nonmetal and forms H- (hydride anions), it is sometimes placed above the halogens in the periodic table. Hydrogen also forms H2 dihydrogen like halogens. However, hydrogen is very different from the halogens. Hydrogen has a much smaller electron affinity than the halogens. H2 dihydrogen or molecular hydrogen is non-polar with two electrons. There are weak attractive forces between H2 molecules, resulting in low boiling and melting points. However, H2 has very strong intramolecular forces; H2 reactions are generally slow at room temperature due to strong H—H bond. H2 is easily activated by heat, irradiation, or catalysis. Activated hydrogen gas reacts very quickly and exothermically with many substances. Hydrogen also has an ability to form covalent bonds with a large variety of substances.

Because it makes strong O—H bonds, it is a good reducing agent for metal oxides. Example: CuO(s) + H2(g) → Cu(s) + H2O(g) H2(g) passes over CuO(s) to reduce the Cu2+ to Cu(s), while getting oxidized itself. Reactions of Hydrogen Hydrogen's low ionization energy makes it act like an alkali metal: \[H_{(g)} \rightarrow H^+_{(g)} + e^-\] However, it half-filled valence shell (with a \(1s^1\) configuration) with one \(e^-\) also causes hydrogen to act like a halogen non-metal to gain noble gas configuration by adding an additional electron \[H_{(g)} + e^- \rightarrow H^-_{(g)}\] Reactions of Hydrogen with Active Metals Hydrogen accepts e- from an active metal to form ionic hydrides like LiH. By forming an ion with -1 charge, the hydrogen behaves like a halogen.

Group 1 metals \(Ca_{(s)}+H_{2(g)} \rightarrow CaH_{2(s)}\) \(Ca_{(s)}+Cl_{2(g)} \rightarrow CaCl_{2(s)}\) Reactions of Hydrogen with Nonmetals Unlike metals forming ionic bonds with nonmetals, hydrogen forms polar covalent bonds. Despite being electropositive like the active metals that form ionic bonds with nonmetals, hydrogen is much less electropositive than the active metals, and forms covalent bonds. Hydrogen + Halogen → Hydrogen Halide \[H_{2(g)}+ Cl_{2(g)} \rightarrow HCl_{(g)}\] Hydrogen gas reacting with oxygen to produce water and a large amount of heat: Hydrogen + Oxygen → Water \[(H_{2(g)}+O_{2(g)} \rightarrow H_2O_{(g)}\] Reactions with Transition Metals Reactions of hydrogen with Transition metals (Group 3-12) form metallic hydrides. There is no fixed ratio of hydrogen atom to metal because the hydrogen atoms fill holes between metal atoms in the crystalline structure.

Uses & Application The vast majority of hydrogen produced industrially today is made either from treatment of methane gas with steam or in the production of "water gas" from the reaction of coal with steam. Most of this hydrogen is used in the Haber process to manufacture ammonia. Hydrogen is also used for hydrogenation vegetable oils, turning them into margarine and shortening, and some is used for liquid rocket fuel. Liquid hydrogen (combined with liquid oxygen) is a major component of rocket fuel (as mentioned above combination of hydrogen and oxygen relapses a huge amount of energy). Because hydrogen is a good reducing agent, it is used to produce metals like iron, copper, nickel, and cobalt from their ores. Because one cubic feet of hydrogen can lift about 0.07 lbs, hydrogen lifted airships or Zeppelins became very common in the early 1900s.However, the use of hydrogen for this purpose was largely discontinued around World War II after the explosion of The Hindenburg; this prompted greater use of inert helium, rather than flammable hydrogen for air travel. Video Showing the explosion of The Hindenburg.

(Video from Youtube) Recently, due to the fear of fossil fuels running out, extensive research is being done on hydrogen as a source of energy.Because of their moderately high energy densities liquid hydrogen and compressed hydrogen gas are possible fuels for the future.A huge advantage in using them is that their combustion only produces water (it burns “clean”). However, it is very costly, and not economically feasible with current technology. Combustion of fuel produces energy that can be converted into electrical energy when energy in the steam turns a turbine to drive a generator. However, this is not very efficient because a great deal of energy is lost as heat. The production of electricity using voltaic cell can yield more electricity (a form of usable energy). Voltaic cells that transform chemical energy in fuels (like H2 and CH4) are called fuel cells. These are not self-contained and so are not considered batteries. The hydrogen cell is a type of fuel cell involving the reaction between H2(g) with O2(g) to form liquid water; this cell is twice as efficient as the best internal combustion engine. In the cell (in basic conditions), the oxygen is reduced at the cathode, while the hydrogen is oxidized at the anode.

Reduction: O2(g)+2H2O(l)+4e- → 4OH-(aq) Oxidation: H2(g) + 2OH-(aq) → 2H2O(l) + 2e- Overall: 2H2(g) + O2(g) → 2H2O(l) E°cell= Reduction- Oxidation= E°O2/OH- - E°H2O/H2 = 0.401V – (-0.828V) = +1.23 However, this technology is far from being used in everyday life due to its great costs. Image of A Hydrogen Fuel Cell. (Image made by Ridhi Sachdev) Natural Occurrence & Other Sources Naturally Occurring Hydrogen Hydrogen is the fuel for reactions of the Sun and other stars (fusion reactions). Hydrogen is the lightest and most abundant element in the universe. About 70%- 75% of the universe is composed of hydrogen by mass. All stars are essentially large masses of hydrogen gas that produce enormous amounts of energy through the fusion of hydrogen atoms at their dense cores.

In smaller stars, hydrogen atoms collided and fused to form helium and other light elements like nitrogen and carbon(essential for life). In the larger stars, fusion produces the lighter and heavier elements like calcium, oxygen, and silicon. On Earth, hydrogen is mostly found in association with oxygen; its most abundant form being water (H2O). Hydrogen is only .9% by mass and 15% by volume abundant on the earth, despite water covering about 70% of the planet. Because hydrogen is so light, there is only 0.5 ppm (parts per million) in the atmosphere, which is a good thing considering it is EXTREMELY flammable. Other Sources of Hydrogen Hydrogen gas can be prepared by reacting a dilute strong acid like hydrochloric acids with an active metal. The metal becomes oxides, while the H+ (from the acid) is reduced to hydrogen gas.

This method is only practical for producing small amounts of hydrogen in the lab, but is much too costly for industrial production: \[Zn_{(s)} + 2H^+_{(aq)} \rightarrow Zn^{2+}_{(aq)} + H_{2(g)}\] The purest form of H2(g) can come from electrolysis of H2O(l), the most common hydrogen compound on this plant. This method is also not commercially viable because it requires a significant amount of energy (\(\Delta H = 572 \;kJ\)): \[2H_2O_{(l)} \rightarrow 2H_{2(g)} + O_{2(g)} \] \(H_2O\) is the most abundant form of hydrogen on the planet, so it seems logical to try to extract hydrogen from water without electrolysis of water. To do so, we must reduce the hydrogen with +1 oxidation state to hydrogen with 0 oxidation state (in hydrogen gas). Three commonly used reducing agents are carbon (in coke or coal), carbon monoxide, and methane.

These react with water vapor form H2(g): \[C_{(s)} + 2H_2O_{(g)} \rightarrow CO(g) + H_{2(g)}\] \[CO_{(g)} + 2H_2O_{(g)} \rightarrow CO2 + H_{2(g)}\] Reforming of Methane: \[CH_{4(g)} + H_2O_{(g)} \rightarrow CO(g) + 3H_{2(g)}\] These three methods are most industrially feasible (cost effective) methods of producing H2(g). Isotopes There are two important isotopes of hydrogen. Deuterium (2H) has an abundance of 0.015% of terrestrial hydrogen and the nucleus of the isotope contains one neutron. Figure : Three Hydrogen Isotopes (Image Made by of Ridhi Sachdev) Protium (1H) is the most common isotope, consisting of 99.98% of naturally occurring hydrogen. It is a nucleus containing a single proton.

Deuterium (2H) is another an isotope containing a proton and neutron, consisting of only 0.0156% of the naturally occurring hydrogen. Commonly indicated with symbol D and sometimes called heavy hydrogen, deuterium is separated by the fractional distillation of liquid hydrogen but it can also be produced by the prolonged electrolysis of ordinary water. Approximately 100,000 gallons of water will produce a single gallon of D2O, "heavy water". This special kind of water has a higher density, melting point, and boiling point than regular water and used as a moderator in some fission power reactors. Deuterium fuel is used in experimental fusion reactors. Replacing protium with deuterium has important uses for exploring reaction mechanisms via the kinetic isotope effect . Tritium (3H) contains two neutrons in its nucleus and is radioactive with a 12.3-year half-life, which is continuously formed in the upper atmosphere due to cosmic rays. It is can also be made in a lab from Lithium-6 in a nuclear reactor. Tritium is also used in hydrogen bombs.

It is very rare (about 1 in every 1,018 atoms) and is formed in the environment by cosmic ray bombardment. Most tritium is manufactured by bombarding Li with neutrons. Tritium is used in thermonuclear weapons and experimental fusion reactors. References Shultz, M., Kelly, M., Paritsky, L., Wagner, J. A Theme-Based Course: Hydrogen as the Fuel of the Future. Journal of Chemical Education Rigden, John. Hydrogen: The Essential Element. The President and Fellows of Harvard College. 2003. Banks, Alton. Hydrogen. 1989 66 (10), 801. Petrucci, Ralph H. General Chemistry. 9th ed. Upper Saddle River: Prentice Hall, 2007. Print Sadava, Heller, Orians, Purves, Hillis. Life The Science of Biology. 8th ed. Sunderland, MA: W.H. Freeman, 2008. Dinga, G. Hydrogen:The ultimate fuel and energy carrier.

Journal of Chemical Education Hydrogen»the essentials [WebElements Periodic Table] Element News Hydrogen: the essentials Note that while hydrogen is normally shown at the top of the Group 1 elements in the periodic table, the term "alkaline metal" refers to the Group 1 elements from lithium downwards and not hydrogen. Hydrogen is the lightest element. It is by far the most abundant element in the universe and makes up about about 90% of the universe by weight. It is also the most abundant element in the earth's sun. Hydrogen as water (H2O) is absolutely essential to life and it is present in all organic compounds. Hydrogen is the lightest gas. Hydrogen gas was used in lighter-than-air balloons for transport but is far too dangerous because of the fire risk (Hindenburg). It burns in air to form only water as waste product and if hydrogen could be made on sufficient scale from other than fossil fuels then there might be a possibility of a hydrogen economy. CAS Registry ID : 1333-74-0 Hydrogen: historical information Hydrogen was discovered by Henry Cavendish in 1766 at London, England.

Origin of name : from the Greek words "hydro" and "genes" meaning "water" and "generator". Robert Boyle (1627-1691; English chemist and physicist) published a paper ("New experiments touching the relation betwixt flame and air") in 1671 in which he described the reaction between iron filings and dilute acids which results in the evolution of gaseous hydrogen ("inflammable solution of Mars" [iron]). However it was only much later that it was recognized as an element by Henry Cavendish (1731-1810; an English chemist and physicist who also independently discovered nitrogen) in 1766 when he collected it over mercury and described it as "inflammable air from metals". Cavendish described accurately hydrogen's properties but thought erroneously that the gas originated from the metal rather than from the acid. Hydrogen was named by Lavoisier. Deuterium gas (2H2, often written D2), made up from deuterium, a heavy isotope of hydrogen, was discovered in 1931 by Harold Urey, a professor of chemistry at Chicago and California (both USA).

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for hydrogen is shown below. [See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.] In 1839 a British scientist Sir William Robert Grove carried out experiments on electrolysis. He used electricity to split water into hydrogen and oxygen.

He then argued one should be able to reverse the electrolysis and so generate electricity from the reaction of oxygen with hydrogen. He enclosed platinum strips in separate sealed bottles, one containing hydrogen and one oxygen. When the containers were immersed in dilute sulphuric acid a current indeed flowed between the two electrodes and water was formed in the gas bottles. He linked several of these devices in series to increase the voltage produced in a gas battery. Later the term fuel cell was used by the chemists Ludwig Mond and Charles Langer. In 1932 Dr Francis Thomas Bacon, an engineer at Cambridge University in the UK, worked further on designs of Mond and Langer. He replaced the platinum electrodes with less expensive nickel gauze and substituted the sulphuric acid electrolyte for alkaline potassium hydroxide (less corrosive to the electrodes). This was in essence the first alkaline fuel cell (AFC) and was called the Bacon Cell. It took Bacon another 27 years to demonstrate a machine capable of producing 5 kW of power, enough to power a welding machine. At about the same time the first fuel cell powered vehicle was demonstrated. Much later fuel cells were by NASA in the 1960s for the Apollo space missions.

Fuel cells have been used for more than 100 missions in NASA spacecraft. Fuel cells are also used in submarines. The lifting agent for the ill fated Hindenberg ballooon was hydrogen rather than the safer helium. The image below is the scene probably in a way you have not seen it before. This is a "ray-traced" image reproduced with the permission of Johannes Ewers , the artist, who won first place with this image in the March/April 1999 Internet Raytracing Competition . For details of ray-tracing you can't beat the POV-Ray site. Hydrogen around us Read more » Hydrogen makes up two of the three atoms in water and water is absolutely essential to life. Hydrogen is present in all organic compounds. A form of water in which both hydrogen atoms are replaced by deuterium (2H, or D) is called "heavy water" (D2O) and is toxic to mammals. Some bacteria are known to metabolise molecular hydrogen (H2). H2 gas is present in the earth's atmosphere in very small quantities, but is present to a far greater extent chemically bound as water (H2O) Water is a constituent of many minerals.

Hydrogen is the lightest element and is by far the most abundant element in the universe, making up about about 90% of the atoms or 75% of the mass, of the universe. Hydrogen is a major constituent of the the sun and most stars. The sun burns by a number of nuclear processes but mainly through the fusion of hydrogen nuclei into helium nuclei. Hydrogen is a major component of the planet Jupiter. In the planet's interior the pressure is probably so great that solid molecular hydrogen is converted into solid metallic hydrogen. Abundances for hydrogen in a number of different environments. More abundance data » Location Second ionisation energy : (no data) kJ mol‑1 Isolation Isolation : in the laboratory, small amounts of hydrogen gas may be made by the reaction of calcium hydride with water. CaH2 + 2H2O → Ca(OH)2 + 2H2 This is quite efficient in the sense that 50% of the hydrogen produced comes from water. Another very convenient laboratory scale experiment follows Boyle's early synthesis, the reaction of iron filings with dilute sulphuric acid.

Fe + H2SO4 → FeSO4 + H2 There are many industrial methods for the production of hydrogen and that used will depend upon local factors such as the quantity required and the raw materials to hand. Two processes in use involve heating coke with steam in the water gas shift reaction or hydrocarbons such as methane with steam. CH4 + H2O (1100°C) → CO + 3H2 C(coke) + H2O (1000°C) → CO + H2 In both these cases, further hydrogen may be made by passing the CO and steam over hot (400°C) iron oxide or cobalt oxide. CO + H2O → CO2 + H2 Read more » The Hydrogen isotope H-2, also known as deuterium, is used in a variety of applications. Deuterium is used extensively in organic chemistry in order to study chemical reactions. It is also used in vitamin research. Deuterium in the form of H2O, known as heavy water, is used as a moderator in CANDU nuclear reactors, in NMR studies and in studies into human metabolism.

Heavy water is also applied in the Sudbury Neutrino Observatory where it is used to study the behavior of neutrinos. Isotopes of Hydrogen About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Isotopes of Hydrogen Hydrogen has three naturally occurring isotopes: protium, deuterium and tritium. Each isotope has different chemical properties. Learning Objective Discuss the chemical properties of hydrogen's naturally occurring isotopes. Key Points Protium is the most prevalent hydrogen isotope , with an abundance of 99.98%. It consists of one proton and one electron . It is typically not found in its monoatomic form, but bonded with itself (H2) or other elements . Deuterium is a hydrogen isotope consisting of one proton, one neutron and one electron. It has major applications in nuclear magnetic resonance studies.

Tritium is a hydrogen isotope consisting of one proton, two neutrons and one electron. It is radioactive, with a half-life of 12.32 years. Terms Full Text Properties of Isotopes of Hydrogen Hydrogen has three naturally occurring isotopes: 1H (protium), 2H (deuterium), and 3H (tritium). Other highly unstable nuclei (4H to 7H) have been synthesized in the laboratory, but do not occur in nature. The most stable radioisotope of hydrogen is tritium, with a half-life of 12.32 years. All heavier isotopes are synthetic and have a half-life less than a zeptosecond (10-21 sec). Of these, 5H is the most stable, and the least stable isotope is 7H . Protium, the most common isotope of hydrogen, consists of one proton and one electron. Unique among all stable isotopes, it has no neutrons. Protium 1H is the most common hydrogen isotope with an abundance of more than 99.98%.

The nucleus of this isotope consists of only a single proton (atomic number = mass number = 1) and its mass is 1.007825 amu. Hydrogen is generally found as diatomic hydrogen gas H2, or it combines with other atoms in compounds —monoatomic hydrogen is rare. The H–H bond is one of the strongest bonds in nature, with a bond dissociation enthalpy of 435.88 kJ/mol at 298 K. As a consequence, H2 dissociates to only a minor extent until higher temperatures are reached. At 3000K, the degree of dissociation is only 7.85%. Hydrogen atoms are so reactive that they combine with almost all elements. Deuterium 2H, or deuterium (D), is the other stable isotope of hydrogen. It has a natural abundance of ~156.25 ppm in the oceans, and accounts for approximately 0.0156% of all hydrogen found on earth.

The nucleus of deuterium, called a deuteron, contains one proton and one neutron (mass number = 2), whereas the far more common hydrogen isotope, protium, has no neutrons in the nucleus. Because of the extra neutron present in the nucleus, deuterium is roughly twice the mass of protium (deuterium has a mass of 2.014102 amu, compared to the mean hydrogen atomic mass of 1.007947 amu). Deuterium occurs in trace amounts naturally as deuterium gas, written 2H2 or D2, but is most commonly found in the universe bonded with a protium 1H atom, forming a gas called hydrogen deuteride (HD or 1H2H). Chemically, deuterium behaves similarly to ordinary hydrogen (protium), but there are differences in bond energy and length for compounds of heavy hydrogen isotopes, which are larger than the isotopic differences in any other element. Bonds involving deuterium and tritium are somewhat stronger than the corresponding bonds in protium, and these differences are enough to make significant changes in biological reactions.

Deuterium can replace the normal hydrogen in water molecules to form heavy water (D2O), which is about 10.6% denser than normal water. Heavy water is slightly toxic in eukaryotic animals, with 25% substitution of the body water causing cell division problems and sterility, and 50% substitution causing death by cytotoxic syndrome (bone marrow failure and gastrointestinal lining failure). Consumption of heavy water does not pose a health threat to humans. It is estimated that a 70 kg person might drink 4.8 liters of heavy water without serious consequences. The most common use for deuterium is in nuclear resonance spectroscopy. As nuclear magnetic resonance (NMR) requires compounds of interest to be dissolved in solution , the solution signal should not register in the analysis. As NMR analyzes the nuclear spins of hydrogen atoms, the different nuclear spin property of deuterium is not 'seen' by the NMR instrument, making deuterated solvents highly desirable due to the lack of solvent-signal interference . The three naturally occurring isotopes of hydrogen. Tritium 3H is known as tritium and contains one proton and two neutrons in its nucleus (mass number = 3).

It is radioactive, decaying into helium-3 through beta-decay accompanied by a release of 18.6 keV of energy. It has a half-life of 12.32 years. Naturally occurring tritium is extremely rare on Earth, where trace amounts are formed by the interaction of the atmosphere with cosmic rays. Heavier Synthetic Isotopes 4H contains one proton and three neutrons in its nucleus. It is a highly unstable isotope of hydrogen. It has been synthesized in the laboratory by bombarding tritium with fast-moving deuterium nuclei. In this experiment, the tritium nuclei captured neutrons from the fast-moving deuterium nucleus. The presence of the hydrogen-4 was deduced by detecting the emitted protons. Its atomic mass is 4.02781 ± 0.00011 amu. It decays through neutron emission with a half-life of 1.39 ×10−22 seconds. 5H is another highly unstable heavy isotope of hydrogen. The nucleus consists of a proton and four neutrons. It has been synthesized in a laboratory by bombarding tritium with fast-moving tritium nuclei.

One tritium nucleus captures two neutrons from the other, becoming a nucleus with one proton and four neutrons. The remaining proton may be detected and the existence of hydrogen-5 deduced. It decays through double neutron emission and has a half-life of at least 9.1 × 10−22 seconds. 6H decays through triple neutron emission and has a half-life of 2.90×10−22 seconds. It consists of one proton and five neutrons. 7H consists of one proton and six neutrons. It was first synthesized in 2003 by a group of Russian, Japanese and French scientists at RIKEN's RI Beam Science Laboratory, by bombarding hydrogen with helium-8 atoms. The helium-8's neutrons were donated to the hydrogen's nucleus. The two remaining protons were detected by the "RIKEN telescope", a device composed of several layers of sensors, positioned behind the target of the RI Beam cyclotron.

Question: In chemistry, Heavy Hydrogen is another term for what?
Answer: Deuterium